Can you tell me whether a driver is obligated to make a right on red at an intersection where there are signs posted that you may? I have seen occasions recently when the following driver has gotten all worked up over the first car not turning.

Robert Thomson is The Washington Post’s “Dr. Gridlock.” He answers travelers’ questions, listens to their complaints and shares their pain on the roads, trains and buses in the Washington region. View Archive

DG: Nitschke sent in this question via e-mail. The sign-off at the end of the e-mail was, “Please make your car a no-phone zone.” I like that. “We need to stigmatize distracted driving,” safety officials repeatedly tell me, and we can do this with some peer-to-peer pressure similar to the grass-roots effort that stigmatized drunken driving.

Back to Nitschke’s question, which comes up a lot in various forms. Sometimes, it’s about when to make a left turn on a green light.

The basic issue is when a driver should move into an intersection. The basic answer is: Move when you think it’s safe. Don’t do it because the driver behind you thinks it’s safe.

And I mean safe for everybody, including the other cars that might be entering the intersection and the pedestrians who might be using the crosswalks. It’s dismayingly common to hear a waiting driver honk at the driver ahead because that driver has failed to turn into the path of a pedestrian.

There is no legal obligation to turn right on red where that is permitted, and there is a legal obligation to yield to pedestrians in crosswalks, as well as to yield to other motorists in intersections.

On the other hand, it’s discourteous and inefficient to hold up traffic if the coast is clear. Don’t use the red light as an excuse to check your map or check your messages if you were going to turn right anyway. The motorist behind you will see your right turn signal working and also detect that you’re not focused on your driving.

It’s fine to pay attention to the following driver, as long as you’re putting safety first.

More about ‘Minus’

Dear Dr. Gridlock:

I do not know why Blue Line riders are complaining about Rush Plus and calling it “Rush Minus.” After all, those of us who have taken the Red Line toward Shady Grove have had to deal with Rush Minus for years.

And we have always had to pay more than anyone else for this reduced service. Having only half the trains go all the way out to Shady Grove makes those trains extra crowded, and the trips take longer than they would if all the trains went to the end of the line.

DG: Many riders don’t think of the transit system as “Metro.” They think of it as a color. Maybe two colors, if they transfer between lines.

And they guard their colors. Like drivers, they’re naturally focused on the quality of the commute along their own route, and many compare their level of service with what they perceive is going on elsewhere in the system.

For rush-hour commuters bound for the far west portion of the Red Line, it’s frustrating to get dumped out on the platform at the Grosvenor-Strathmore station, where they must wait for a through train to Shady Grove.

It’s no consolation to tell them that many Glenmont-bound riders on the other side of the line endure a similar delay at Silver Spring, or that the Red Line has more rail cars than the other lines, or that the situation was worse before money was added in 2006 to limit the off-peak turnbacks at Grosvenor.

Metro turns back some Red Line trains at rush hour to get trains into the rail system’s core to ease congestion on the most crowded platforms. Metro uses a similar strategy when it sweeps baseball fans onto Green Line trains at the crowded Navy Yard-Ballpark station platform, but it takes some of them only as far north as Mount Vernon Square, where they have to debark and wait for a through train to Greenbelt. Meanwhile, the train they were kicked off heads back south to pick up people at Navy Yard.

I can’t offer much hope to those Red Line riders. The long-term capital budget includes money for more rail cars, but only enough to account for the new service on the Silver Line and the replacement of the oldest cars in the fleet. There’s nothing specifically tagged to end the turnbacks.

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